Disable copy & paste content from outside source of WPF installer

Question

I am trying to disable Copy/Paste/Cut feature in special window in xaml(WPF).

I set the PreviewKeyDown="Window_PreviewKeyDown" in properties of special window. This way any key down it will track and cancel. Below code is working fine for disallow copy & paste for outside.

private void Window_PreviewKeyDown(object sender, KeyEventArgs e)
        {
            if(Keyboard.Modifiers == ModifierKeys.Control && (e.Key == Key.C || e.Key == Key.X))
            {
                e.Handled = true;
            }
            if(Keyboard.Modifiers == ModifierKeys.Control && e.Key == Key.V)
            {
                e.Handled = true;
            }
        }

This works

Now, I would like to allow copying and pasting from within the application itself.

Is there a way to disallow outside copy pasting into an application except for what has been copied and pasted from with an application?

Answer 1

Here is the answer. We need to clear the clipboard when deactivate the window and can be set the text again into clipboard while activate.

private string oldClipboardContent { get; set; } = "";

 private void Window_Activated(object sender, EventArgs e)
        {
            Clipboard.SetText(oldClipboardContent);
        }

        private void Window_Deactivated(object sender, EventArgs e)
        {
            oldClipboardContent = Clipboard.GetText();
            Clipboard.Clear();
        }